CIALDI, ALESSANDRO. - Navigator and devotee of hydraulic and nautical sciences, pontifical naval officer, b. at Civitavecchia on 9 April 1807, d. at Rome on 16 June 1882. In 1840, with the rank of captain in command of a small naval squadron, he sailed for the first time with European vessels up the Nile for 1164 km from its mouth, and, having carved the name of Gregory XVI on the temple of Isis on the island of Philae, he returned to Rome (28 Aug. 1841), bringing a precious collection of material and of archaeological, nautical and naturalistic information, together with four large alabaster parallelepipeds donated by the viceroy of Egypt to the Pontiff for the resurgent basilica of St. Paul Outside the Walls.
It was thanks to C. that a modest but well-organized and well-led pontifical fleet was able in 1848 to operate successfully in the Adriatic, alongside the other Italian fleets, against the Austrian one, and in 1860 managed to promptly resupply with arms and ammunition the fortress of Ancona, already on the point of being encircled by siege. In 1867 he shrewdly thwarted bold Garibaldian attempts at raiding and landing along the coasts of Latium and on the course of the Tiber, such as that of the Cairoli; nor did C. remain inactive with his sailors in 1870 in the face of the rapid precipitation of events.
From that time on, faithful to the Pontiff, he withdrew to private life to devote himself to his favorite studies: mention should be made of the regularization of the courses of the Tiber and the Serchio; the works of improvement and perfecting of the ports of Livorno, Genoa, Pesaro, Civitavecchia, Fiumicino and Anzio; the not negligible contribution offered in supporting and technically and financially backing the cutting of the Isthmus of Suez and the very conduct of the works, also as a member of the special pontifical Commission; the work carried out for the implementation and the complete and rational illumination of the coasts of the Tyrrhenian landings of the Roman State. C.'s principal scientific merit was the discovery and definitive formulation of the hydrodynamic theory of wave motion and of the coastal currents of the sea, for which, on 11 March 1878, the Academy of Sciences of Paris numbered him among its members, while already since 1847 he belonged to the pontifical Academy of the Nuovi Lincei, and in 1879 he became its president, succeeding Angelo Secchi. At his death C. left the city of Civitavecchia as heir to his rich and rare scientific library, in whose cemetery he was buried with an epitaph composed by the historian of the pontifical navy Alberto Guglielmetti.
Among C.'s works, amounting to more than fifty, particular mention should be made of: Relation de deux voyages exécutés par la marine militaire des Etats Romains dans les années 1840-42, in Annales maritimes et coloniales (Paris 1843); Sul Tevere, sulla linea più conveniente per la unione dei due mari e sulla marina mercantile dello Stato Pontificio (Rome 1847); Sul moto ondoso del mare e sulle correnti di esso specialmente su quelle litorali (ibid. 1843; 2nd ed. greatly enlarged, ibid. 1846); Port Said, A M. F. De Lesseps..., lettre du comm. A. C., etc. (ibid. 1868); Nozioni preliminari per un trattato sulla costruzione dei porti sul Mediterraneo (ibid. 1874); Illuminazione e segnalamento dei litorali e dei porti (ibid. 1878).
Bibliography7 works
Paolo Dalla Torre